A gas turbine includes a compressor that generates compressed air, a combustor that combusts fuel in the compressed air to generate combustion gas, and a turbine that is driven in rotation by the combustion gas. The combustor includes a combustor basket where fuel and air are supplied and a transition piece where combustion gas is generated after the fuel and air supplied to the combustor basket are ignited therein.
In some conventional gas turbines, film air is supplied from a gap between the outer ring of the outlet that composes a leading end portion of the combustor basket and the transition piece to prevent the combustion gas generated in the transition piece from damaging the internal wall surface of the transition piece.
It is common for actual gas turbines to have a configuration with a plurality of combustors disposed around the periphery of the gas turbine and these combustors being connected via a connecting pipe. In such a configuration, one combustor is provided with an ignition plug, and the flame produced in this combustor is then spread to other combustors via the connecting pipe to ignite all of the combustors. When combustors are provided with a connecting pipe as such, specifically, an opening is formed in the wall of the combustor basket of the combustor, and adjacent combustors are connected at the opening via the connecting pipe. Additionally, such a connecting pipe needs to be protected from the heat by film air in the same manner as the combustor basket and the transition piece of the combustors.
Patent Document 1 describes known technology for protecting a connecting pipe via film air. In the combustor described in Patent Document 1, the inside of the connecting pipe (bypass pipe) is provided with a sleeve that defines a flow channel. By supplying air through the flow channel, the side wall of the bypass pipe is supplied with film air.